what's the difference between these two pointer code

Question

I found these two different sources, but they do the exact same thing. I was wondering if there is a difference or not but I couldn't figure it out.

Can anyone tell me the difference and when should I use which?

this is the first one:

void function1(int *x) {
    *x = 100;
}

int main() {
    int var1 = 10;

    function1(&var1);
    cout << var1 << endl;
}

and this is the second one:

void function2(int &x) {
    x = 100;
}

int main() {
    int var2 = 10;

    function2(var2);
    cout << var2 << endl;
}

In `function1`, `nullptr` is a valid argument (which should be checked). — Jarod42, Jun 10 '16 at 16:34
There are style convention which prefers pointers for modified objects. — Jarod42, Jun 10 '16 at 16:36
[Strongly related](http://stackoverflow.com/questions/114180/pointer-vs-reference) — Nic, Jun 10 '16 at 16:36

score 2 · Accepted Answer · answered Jun 10 '16 at 16:33

2

int *x is a pointer whereas int &x is a reference. Probably the biggest difference is that you can't change where reference is pointing to.

answered Jun 10 '16 at 16:33

Jan Korous

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4
11

score 0 · Answer 2 · answered Jun 10 '16 at 16:37

The first is a pointer, the second is a reference. The ideas have some similarities, but there are also differences.

A pointer is a C and C++ mechanism and a bit more "pure" but gives you more posibilies for advanced concepts like pointer arithmetics. References are C++ only and are more safe and more implicit, as a reference is used with the same syntax as a normal varible while using the referenced one. A pointer is more explicit if you want to use or change its value, as you have to explicitely dereference it using *var, and explicitely have obtain it.

what's the difference between these two pointer code

2 Answers2